When employing optical cable, which typically includes optical fiber having core and cladding surrounded by some form of sheathing, there may be the necessity to run or suspend the cable between two longitudinal distant sections. Such is the case in optical terminations and connections. In addition, most cable structures will often be exposed to tensile loads placed thereon. Any physical stress placed on the cable by such loads will be transmitted to the fiber itself. This transmitted stress, which may be a part of normal handling of the cable or the result of the aforementioned axial loads placed thereon, could cause damage to the fiber, resulting in a decrease or possible total loss of optical transmission capability.
In order to reduce the amount of stress transmitted from the jacketed cable to the fiber, it is known to provide excess fiber within the cable. This excess fiber may be formed by periodically providing fiber slack within the cable to allow a certain amount of "give", thereby preventing equivalent tensile stress from being transmitted from the cable, to the fiber. While transmited stress will be substantially reduced in this manner, it will not be totally prevented. Repeated or continuous stress caused by an axial load may tend to be transmitted, to a limited degree, to the fiber, thereby affecting the quality of optical transmission. Further, this type of strain relief must be provided for during fiber construction and cannot be provided during subsequent use.
Beyond the above, the optical termination art has seen alternative connector structures which attempt to provide for strain relief in optical cable by providing excess fiber within the connector itself. Optical fiber cable, regardless of previous provisions for strain relief in the cable, could be terminated in a connector which by providing excess therein, reduces the transmitted stress to the fiber. Such a connector is set forth in U.S. Pat. No. 3,871,744 issued Mar. 18, 1975. This patent discloses an optical fiber connector which provides excess cable within the terminating structure for strain relief. The structure employs a removable thumb screw which can be internally rotated to bear transversely against the fiber, thereby "bowing" the fiber and providing excess fiber within the connector. This method of providing strain relief requires "blind" contacting of the fiber with the thumb screw. Overinsertion of the screw may cause damage to the optical fiber, while underinsertion will fail to produce the desired results.
It is desirable to provide an improved optical fiber connector which can be easily and inexpensively manufactured and which will provide strain relief by allowing for excess fiber within the cable assembly. It is also desirable to provide such excess without the need to bear transversely against the fiber in order to minimize or eliminate the possibility of damage to the fiber.